Based on a Bluetooth standard, an OPP (Object Push Profile) is defined as a versatile communication profile used to transmit/receive object data such as image data. In contrast to this, recently, a BIP (Basic Imaging Profile) has been developed as a communication profile dedicated to image data transfer. Upon using this BIP, various negotiations about the format, size, and the like of image data to be transmitted can be performed. Also, this BIP has also been studied to be used as the communication profile in image data wireless transmission between the digital camera and the printer device.
FIG. 2 is a schematic view showing a conventional Bluetooth wireless communication system. In FIG. 2, a notebook PC 201 connects with a Bluetooth device as a USB-adapter access point device which supports both the protocols BIP and OPP. A wireless printer device 202 incorporates a Bluetooth device which supports the BIP. Each of a wireless digital camera 203 and a cellular phone 204 incorporates a Bluetooth device which supports the OPP.
Since the notebook PC 201 supports both the protocols BIP and OPP, it can transmit/receive object data to/from the wireless printer device 202, wireless digital camera 203, and cellular phone 204.
The wireless printer device 202 supports a communication protocol different from that of the wireless digital camera 203 and cellular phone 20.4. Hence, the wireless digital camera 203 and the cellular phone 204 can neither directly transmit object data to the wireless printer device 202 nor output an image file or the like. Therefore, in order to output the image file or the like to the wireless printer device 202, the object data to be output must be temporarily transferred and saved in the notebook PC 201. After that, the object data must be transferred to the wireless printer device 202 by using a communication application on the notebook PC 201. Hence, strong demand has arisen for a short object data transfer time.
Under these circumstances, some schemes for shortening the transfer time have been proposed. For example, Japanese Patent Laid-Open No. 2001-051803 discloses a block data transfer mechanism for forming composite variable length block data by collecting a plurality of block data when small-size or unfixed-size block data are to be transferred. The transfer time is intended to be shortened by this block data transfer mechanism.
As another scheme pertaining to data transfer, Japanese Patent Laid-Open No. 08-194582 is available. According to this patent reference, an asynchronization transfer count decreases to increase data reference/update processing rate. Additionally, a larger cache memory area is allocated to a data area with a high access frequency (on a magnetic disk) to effectively use a main memory, thereby shortening the data transfer time.
However, in a device such as the notebook PC 201 which supports the plurality of different communication protocols OPP and BIP, different communication protocols are required to be installed depending on mating devices in transmission/reception of object data. Hence, the amount of data handled in one transmission operation changes.
Therefore, even in transmission/reception of the same amount of object data, the data transfer time may change depending on the combination of devices or the communication protocol to be used. Hence, the schemes for shortening the data transfer time, which are disclosed in Japanese Patent Laid Open. Nos. 2001-051803 and 08-194582, cannot be directly applied.